(Field of the Invention)
The present invention relates to a gas supply apparatus and an air or nitrogen supply apparatus of a nuclear plant. The present invention relates to a gas supply apparatus suitable for a part provided with an electromagnetic valve placed in the middle of a piping so as to switch between an operation of opening a valve and an operation of closing the valve, for example, an air-operated valve placed in the nuclear plant and an air or nitrogen supply apparatus of a nuclear plant.
(Description of Related Art)
Various kinds of plants including a nuclear power plant are installed with piping for letting gas such as air, nitrogen, or steam and liquid such as water flow. The piping is provided with electrically operated valves and air or nitrogen operated valves which are operated by electricity or compressed air or compressed nitrogen activated by an opening operation for letting fluid in the piping flow or a closing operation for stopping the flow or by an electric signal or an air pressure signal to thereby control flow and pressure.
In particular, as to the air or nitrogen operated valve placed in the nuclear plant, in order to switch between an operation of opening a valve and an operation of closing the valve, an electromagnetic valve is placed in the middle of an air or nitrogen piping system. For example, when a station blackout (SBO) is caused, the coil of the electromagnetic valve is non-excited and air or nitrogen from an air or nitrogen supply source is reduced in pressure to thereby perform a failsafe operation. However, after that, electricity cannot be supplied from a power source and the air or nitrogen cannot be supplied from the air or nitrogen supply source, so that the air or nitrogen operated valve cannot be operated, which is likely to produce a trouble in operating the air or nitrogen operated valve thereafter.
In this way, because the electricity cannot be supplied from the power source and the air or nitrogen cannot be supplied from the air or nitrogen supply source, there is a possibility that the air or nitrogen operated valve cannot be operated. Hence, it is required to provide an apparatus that can be safely operated remotely even at the time of an emergency (for example, when the SBO is caused) and that does not perform an incorrect operation (an unintended operation) at the time of a normal operation (when the power source is secured and a normal operation is performed or during a normal standby).
On the other hand, a technique that can safely process hydrogen to prevent hydrogen explosion and prevent a nuclear reactor building from being broken even in a case in which the SBO is caused and in which the hydrogen generated in a reactor pressure vessel leaks to the inside of the nuclear reactor building is described in Japanese Patent Application Laid-Open No. 2012-230058 (Patent Document 1).